Dental flask



J. T. HUGHESJR DENTAL FLASK 2 Sheets-Sheet 1 Filed March 22, 1948 V mm Z W La T. a \W M a J /2 M M f 6 5 w 3 .2

DENTAL FIQAsx Z Sheets-She s: 2

Filed March 22; 1948 INVENTOR. JAMES T. HUGHESZJR Patented May 29,1951

UNITED STATES PATENT OFFICE DENTAL FLASK James T. Hughes, Jr., Covington, Ky.

Application March 22, 1948, Serial No. 16,151

8 Claims. 1

This invention relates to molding flasks for forming sectional or built-up molds of form'able. material such as plaster of Paris. Specifically, the invention is directed to improvements in dental flasks for the casting of dental plates patterned from wax models.

An object of the present invention is to provide a flask structure for the casting of dental plates, or the like, from waste molds upon which external pressure may be exerted for the purpose of densiflcation and compression.

Another object of the invention is to provide a dental flask of separable casing parts for the production of sectional molds.

A still further object of the invention is to providea flask of separable parts so arranged that they may be opened or closed without displacing or disturbing the investment material or model embedded therein.

It is still a further object of the invention to provide a flask structure which permits the easy removal of the mold sections from the respective parts of the casing.

Still another object of the invention is to'provide a flask, the parts of which can be quickly separated so that access can be had for buildingup the mold or for inspection and removal of the denture casting.

It is another object of the invention to provide means in a dental flask for aligning and locking the separable parts in their relative positions preparatory to subsequent casting operations.

. Further objects and advantages are within the scope of this invention such as relate to the arrangement, operation and function of the related elements of the structure as described in the following specification and illustrated drawings, in which:

Figure l is a top plan view showing a preferred form of my dental flask.

. Figure 2 is a side elevational view of the flask as shown in Figure 1.

Figure 3 is an end elevational view of this de- Figure 4 is a sectional view taken on line 44 of Figure 1 showing the locking means and slide rods of the flask.

Figure 5 is an enlarged cross-sectional view taken on line 55 of Figure 1 showing in dot and dash lines the wax model or denture casting, as the case may be, and the respective parting sur faces of the sectional mold.

Figure 6 is a top plan view of the expander member for the main body part of the dental 2 flask showing in dot and dash lines the main body located thereon.

Figure 7 is a side elevational view of the member showing in dot and dash lines the main body of the flask located thereon.

Figure 8 is a top plan view of a modification of my invention partially broken away with a portion of the cope part removed, and in dot and dash lines a tool for the separation of the cope from the main body of the flask.

Figure 9 is an end elevational view of the modification shown in Figure 8 with a portion thereof broken away.

Figure 10 is a sectional view taken on line I0l0 of Figure 8 showing the self-retracting means of the main body of the flask.

Figure 11 is a top plan view of an additional modification of my dental flask, and

Figure 12 is another modification of the guide and retracting means of the main body of the dental flask.

Referring in detail to the drawings, particularly to the structure shown in Figures 1 to 7 inclusive the invention is disclosed in the form of a dental flask l5 of the three-flask part type, the casing l6 thereof, comprising a drag or lower part ll, 'a central main body or check part 18 and a cope or top part I 9.

The drag I! of the casing is a semi-elliptical receptacle with side walls 20, having tool-slots 200 formed in the outer edge thereof for purposes to be later described, and to close the drag, the side walls are terminated by a flat bottom 2|. Extending from the side are opposed integral lugs 22 having vertically tapered bores 23 therethrough. This part of the flask is completed by a central hole 24 formed through the bottom 2| for the removable reception of the shank 25 of a button-headed punch 26.

The main body or check part [8 of the casing is composed of two opposed side walls or equal sections 21 and 28 respectively, shaped substantially in conformity with the side walls 20 of the drag part. Integrally extended at right angles from the adjacent ends 29 of each section are opposed flanges 30 and 3| having conforming holes 32 therethrough for the reception of guide rods 33.

Each of the guide rods are divided into two portions, the stem 34 thereof being turned and terminated by an enlarged knurled head 35. Further, the stems of these portions are either internally or externally threaded, as the case may be, with the female threaded portion extended through the conformingpairs of holes 32 and adjustably retained therein by threaded engage- 1 to inclusive, by locating the steady-pins 38" of the cheek section within the bores 23. V

For knock-down purposes to be laterdescribed, tool-slots 39 are formed in the uppera'nddow'er annular outer edge of the cheeks ZLand ZB' adjacent the flanges 36 and 3!, also, tapered expander bores 40, of a common axial center are located centrally of thecontiguous faces 4| of the flanges 30*and'3l From the above description it is "evident that therespective sections 27 "and 28 of the cheek part are. movable in parallel relation to one another through slidelengager'nent of'the rods 33 in the fiange '30a'nd 3|. It'is' also apparent that the cheeks are' held i'n'a normal spring urged retracted position, but may; be expanded or opened by' a force sufficient to counteract the springs 36.

The cope lflof the dental flask comprises a flat plate 42, and like the body 18, has'a shapes'ub stantially in conformity with the sidewalls 20, with integral lugs 43, corresponding to those'of the drag part H, extending from opposed sides' thereof. The liigs'difier in'str'uc'ture from those of thei'drag part by provisions for'niaintaining the cope in an assembled lateral position with the main body: l8. Yokes '44'therefore, perform a function as bores 23 of the drag, that'is; retention of the sections 2! and 28 in a positive retracted position. A recess 451 centered in the underside of each lug 43, therebydescribing the y'okes44' as having a top 46' on a plane withthe underside of the plate 42, and a pair of spaced depending legs 4.1.

,A, rectangular locating boss 18' depends integrally from the underside of the plate 42in termediatethe lugs 43, and is so'pos'itioned thereto,that'it is longitudinally bisected'by the com-' mon center line, of the recesses 45;

For knock-down purposes, to' be later described, tool-slots 49' are located in the outer annular edge of the underside of 'the' plate 62' adjacent the lugs '43, where, they register with the slots 39 on assembly of the cope to the cheek part of my dental flask.

In assembly, the cope I9 is placed'flush to'the upper edge of the cheek- IB, with the top portion of the flanges 3B, .and 3| inserted between the legs 47, thereby locking the sections 2T'and' 28 nel shaped body, comprising an aperturedbase' 5| and opposed uprights52' and 53. 'A hole is formed through each upright for the threaded reception of thumb screws 54; These holes are formed about a common center line, which when located vertically from the base 5|, is of a' distance equal to that fromthe"top"edge of the curing the denture material therein.

main body l8 of the casing to the common center line of the expander bores 40. The ends of the screws 54 containing the first threads are coni cal having a tapered surface similar to bore for insertion therein. A locating ridge 55, shaped identically a boss 48 of the cope part, extends from the exposed face of the base 5| intermediate the uprights 52 and 53. The position of the ridge to the base is such that it is longitudinally bisected by thevertical' plane of the common center line of the screws"5'4.'

To manufacture denture castings by means of flask, a molder positions the punch 26 in the drag'part I! of the flask and forms the bottom mold section 56 by leveling-off wet plaster of Paris approximately even with the upper edge 'of'the'walls 20 of the drag. The wax model, reference numeral 51, is then embedded centrally within this mold section. All exposed plaster surfaces thereafter being painted with a material, such aswater glass-to 'prevent'uriion 'of subsequently added plaster sections thereto. The main body' I 8 is next assembled to the drag-locating the steady pins 33in thebores 23. A'dditional'w'et plaster, to form the intermediate mold section 58, is now added to a'depth level with the teeth crowns of the'wax' model 51, dotand dash parting" line 59, where the exposed 1 plaster surface is again painted. The "topmold' sectionis now built-up by applyingwetplasten'at least to the upper edge of the main body I 8; The casing I6 is now sealed and locked byfass'einbling the cope [9" to the main body" '18, locating the flanges 30 and 3 I in the respective recesses.

After a'hardening operation of' the plas'ter the wax of the 'model 51 is liquefied and exhausted from the moldby removal of' the drag part'l'l and mold section 56 from' the main 5553; I8, thereby exposing the false teethroots in the resulting' ino ld cavity; A mold abl' dntufe material is inserted this impressionor' cavi'ty, made by the'wax model, and the drag with the mold section 56 is laid back upon the cheek part for The curing operation includes'the' exertion'of suflicient pressure upon the flask, by meansof clamps'orpres'ses, to evacuateall air therefrom and insure av dental casting which has a true complementary shape as the cavity produced'by the model 51. I

The final operation in the production of dental castings by my flask, includes the removal of the drag and cope parts, the latter by means of tool 6| (Figure 8), from the main body 18 of the flask casing, thus leaving intact the intermediate mold section 58, with the dental plate therein, and the top mold section 60, with a locating groove impressed therein by the boss 48 of the cope pa rt. Heretofore, the knocking out ofiir'ii'shed' casting from a plaster mold has been rathertedious and sometimes injuriousto the finished-product, however the incorporation of an expa sible c'ent'eror cheek'part '[8' in' the structure" o'fmyinvention wedging the tapered ends of the thumb screws 54 in the bores 4|] of the flanges.

In the modified form of the invention shown in Figures 8 to 10 inclusive, there is depicted a simplified means for maintaining the sections 21 and 28 of the main body in their normal closed position and guided parallel relationship. Resilient clips 62, engaged in vertical slots 63 formed in the opposed faces of the respective flanges 30 and 3|, are substituted for the springs 36 of my preferred structure, while guide pins 64 are positioned in the conforming holes 32 of the flanges in place of the rods 33. A perforation 65 has been made in the body of the clips 62 to assure exposure of the bores 40 to the expander 50.

The modification shown in Figure 11 has a main body part comprised of four cheek sections 66,

. 61, G8 and 69 respectively to adjacent ends which are terminated by a flange 10 and H. These flanges are guided and resiliently maintained in a normal closed position by means previously described. This form of my invention also differs from the preferred structure in the neces sity for appropriately locating additional lugs, same as lugs 22 and 43, to the drag and cope parts of the modified casing, and by the number of steady pins required for maintaining the respective parts of the flask in their relative lateral position.

The structure of Figure 12 depicts a modified means for retracting the sections of the cheek part, and consists in centering a countersunk bore 12 about the holes 32 of the flanges 3|, threading the remaining holes 32 in the flanges 30, placing a coiled spring 13 in the bore 12, and finally inserting a threaded guide pin 14 therein to adapt the sections 21 and 28 for reciprocable movement in parallel relationship.

What is claimed is:

1. In a dental flask casing for forming sectional molds, the combination of a drag part, cheek part and cope part, saidfcheek part comprising a plurality of side by side sections the adjacent ends of which'terminate in extended flanges having conforming holes, rods guided in the holes for reciprocable movement of said sections in parallel relationship, and means for locking said sections in closed position by assembling either the drag or cope parts thereto.

2. In a dental flask for forming sectional molds, the combination of a drag part, cheek part and cope part, said cheek part comprising a plurality of side by side sections each having adjacently disposed flanges, a lateral guide rod extending through said aligned holes to permit relative movement between said sections, spring means associated with adjacent end flanges for biasing the sections toward operative closed positions, and flange engaging stop means on the cope part and the drag part for locking the cheek part sec-- tions in closed position by assembling the cope and drag part to the said cheek part.

3. In a dental flask for forming sectional molds, the combination of a drag part, cheek part and I cope part, said check part comprising a plurality of side by side sections each having adjacently 6: associatedwith adjacent end fianges for biasing the sections toward operative closed positions, a boss depended from the underside of the cope part for forming a, locating groove in the upper portion of the mold for engagement with a suitable ridge on said expander tool, and flange. engaging stop means on the cope part and on the drag part for locking the cheek part sections in closed position by assembling the cope and .drag part to the said check part. v

4. In a dental flask, the combination of a check part comprising a plurality of sections the adjacent ends of which terminate in extended flanges having conforming holes, rods guided therein for reciprocable movement of said sections in parallel relationship, said flanges provided with contiguous faces having registerable half-bores centered therein, half -dowels depended from the base of said flanges which serve as steady-pins when said sections are in closed position, a drag part provided with extended lugs having perforations therethrough for lock insertion of the steadypins, and a cope part comprising extended lugs.

5. In a .device for making artificial dentures, the combination of a drag part, cheek part and cope part, said cheek comprising a plurality of sections the adjacent ends of which terminate in outstanding flanges having conforming holes, rods guided therein for reciprocable movement of said sections in parallel relationship, resilient means for maintaining the sections in closed position, said flanges provided with contiguous faces having registerable half-bores centered on the common plane thereof, said half-bores being adapted to receive the cooperative wedge of a suitable expander tool, and means for locking said sections in closed position by assembling either the drag or cope parts thereto.

6. In a dental flask for forming sectional molds, the combination of a drag part, cheek part and cope part, said cheek comprising a plurality of equal sections the adjacent ends of which terminate in extended flanges having conforming holes, rods guided therein for reciprocable movement of said sections in parallel relationship, resilient members mounted to said flanges for maintaining the sections in closed position, said flanges provided with contiguous faces having corresponding half-bores centered on the common plane thereof, half-dowels depended from the base of said flanges which serve as steadypins when the sections are in closed position, said drag part comprising a plurality of extended lugs corresponding to the flanges and perforated for lock reception of the steady-pins, said cope part comprising a plurality of extended lugs corresponding to the flanges and recessed to form a yoke for lock reception of said flanges, and a boss depended from the underside of the cope part for forming a locating groove in the upper portion of the mold.

'7. In a dental flask of the class described, a cheek part comprising a plurality of sections, flanges extended from the adjacent ends thereof having conforming holes therethrough, rod-like members guided therein for reciprocable movement of said sections in parallel relationship, each of said members comprising a stem terminated by opposed heads, coiled springs mounted to said stem intermediate the head and flange for maintaining the sections in closed position.

8. In a dental flask of the class described, a cheek part comprising a plurality of sections, flanges extended from the adjacent ends thereof having conforming holes therethrough, rod-like Number 

